1f62ed00a5
C-SKY MMU would pre-fetch invalid pte entries, and it could work with
flush_tlb_fix_spurious_fault, but the additional page fault exceptions
would reduce performance. So flushing the entry of the TLB would prevent
the following spurious page faults. Here is the test code:
define DATA_LEN 4096
define COPY_NUM (504*100)
unsigned char src[DATA_LEN*COPY_NUM] = {0};
unsigned char dst[DATA_LEN*COPY_NUM] = {0};
unsigned char func_src[DATA_LEN*COPY_NUM] = {0};
unsigned char func_dst[DATA_LEN*COPY_NUM] = {0};
void main(void)
{
int j;
for (j = 0; j < COPY_NUM; j++)
memcpy(&dst[j*DATA_LEN], &src[j*DATA_LEN], 4);
}
perf stat -e page-faults ./main.elf
The amount of page fault traps would be reduced in half with the patch.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.